Packing and debridement are extensively practiced for the management of acute and chronic wounds. Presenting a clean wound free from necrotic tissue, slough, and eschar that would interfere with repair is a most important preparatory step for effective wound healing. The removal of nonviable material reduces the incidence of infection and facilitates healing through the formation of healthy granulation tissue and through re-epithelization.
Packing refers to the filling of a wound or cavity with a sponge or other material. Packing is used to absorb excess wound exudate, along with any bacteria present therein, and to facilitate the formation of granulation tissue. Debridement refers to the removal of necrotic tissue from the wound site until healthy tissue is exposed.
The primary objectives of debridement are to encourage granulation and to prevent infection. A freshly debrided wound will express considerable amounts of serous fluid from the denuded cells. Granulation can be encouraged by preventing such fluid from accumulating and reclotting in the wound.
Various methods of debridement are known. These methods include surgical debridement, liquefaction through autolysis or with the aid of added enzymes, and mechanical debridement wherein the endogenous material is scrubbed or pulled away from the wound by means of a sponge or dressing. The procedure selected by the physician depends on numerous factors including the nature of the wound, the condition of the patient, and the situation in which the wound is presented for management.
The use of gauze sponges woven from bleached cotton yarn for packing and debriding wounds is widely practiced. When applied, such sponges are wetted with saline or other prescribed solutions. Such sponges are believed to be effective for mechanical debridement because their densely packed, twisted fiber, yarn elements in the wet state conform freely to the wound topography and upon partially drying embed themselves in or otherwise attach themselves to the necrotic tissue. When the partially dry sponge is removed, the necrotic tissue adhering thereto is also removed. Under some conditions, woven cotton gauze can be too aggressive so that trauma can result if such gauze is allowed to dry completely before it is removed. Often, to prevent excessive disruption of newly formed granulation tissue, woven cotton gauze is not allowed to dry completely or is redampened prior to its removal.
Typically, a sponge made from woven cotton gauze has multiple plies, e.g. twelve plies, with 20.times.8 yarns per square inch in each ply, so as to provide void volume for holding viscous, purulent exudate. Including the spaces between the plies and the large apertures, such a sponge has a rather limited void volume in which to store wound exudate. However, its highly twisted yarns are effective in wicking and lateral transport of liquids and suspended solids.
Altogether, for the management of acute and chronic wounds, woven cotton gauze has significant limitations. As noted above, such gauze can be too aggressive and is not selective in its adherence to material at the surface of the wound. Moreover, such gauze can shed yarn fragments and particles when opened and unfolded, and especially when cut. Such fragments and particles can contaminate the wound and can be very difficult to remove. Furthermore, being woven from twisted yarns, such gauze has relatively low absorptive capacity. Under some conditions, woven cotton gauze can become wadded in a deep, cavernous, undermined wound.
Nonwoven fabrics, made from entangled fibers, have become widely accepted for use as wound dressings and bandages because of their qualities of absorbent capacity, softness, bulk, low linting, and ease of removal from wounds. Nonwoven fabrics of a type known as spunlace fabrics have been widely accepted for general use sponges, wound dressings, and bandages. Typically, spunlace fabric sponges are made from rayon fibers or blends of rayon and polyester fibers. Spunlace fabrics are exemplified in Buyofsky et al. U.S. Pat. No. 4,693,922 and U.S. Pat. No. 4,735,842.
In contrast with woven gauze sponges, spunlace fabric sponges known heretofore are typically comprised of low density strands and have "cloudy", i.e. indistinct, apertures. When wet, the strands of spunlace fabric sponges known heretofore do not conform readily to the wound surface. Upon drying, such strands do not become as deeply embedded in or as firmly attached to necrotic tissue. Thus, when removed, spunlace fabric sponges known heretofore are less aggressive and may be not entirely effective in removing eschar and necrotic debris. Including their inter-ply spaces, cloudy apertures, and low density strands, spunlace fabric sponges have substantially greater void volumes, as compared to the rather limited void volumes of woven gauze sponges. However, spunlace fabric sponges known heretofore have rather low ability to mechanically debride necrotic tissue.
Despite its limitations, and particularly as compared to spunlace fabrics known heretofore, woven cotton gauze has remained a preferred material for sponges used to pack and debride wounds.
There has been a need, to which this invention is addressed, for a debridement sponge combining the best features of woven gauze sponges and spunlace fabric sponges known heretofore without the significant limitations of either.